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The mapping keyword doesn't create a new type, it creates a single variable which can be used like a python dict, where the keys are the type before the => and the values are the type after the =>.

If you're trying to access the users variable from within solidity, useusers[name] to get the address of the user named name, or users[name] = someaddress to assign someaddress to the user named name.

If you're trying to access the users variable from JavaScript, use: contractName.users(name) where contractName is the name of your contract. As long as users is public, this just works. Unfortunately, there's no automatic way to assign from javascript.